Forced off child tax onto uc in April 17 when I tried to claim jsa. My child element has been reduce

Hi. I have been suffering with anxiety and depression for some years now and after a 2 year break from claiming jsa previously  after the continuous mistakes and sanctions they were in plying on me all the time I decided I couldn't deal with the lies they told ect and no longer claimed it as the stress was making me sick. I had to survive on 200 ctc a week for me and my 4 children as a single mother. After the 2 year break I decided I couldn't manage any 
longer relying on my children's ctc and went to make a claim online for jsa again which was a single claim just for myself. It would not allow me to do this and diverted me to do a claim for uc. I was under the impression this claim for uc was a single claim too so I made the claim. I first attended the job centre in April 2017 for my I'd and tenancy scanning ect and was then told that my children had to come onto this same claim automatically because I had made a single claim for uc myself. There was no information on any choices I may of had or any advice on my ctc being stopped as a result they just stopped my ctc and said my children had to go on my claim or I couldn't claim. I made the initial claim in the hope of being able to be better off financially and not have you rely on my children's ctc. Ever since I claimed I've had nothing but a huge loss every month and unbelievable sanctions. These sanctions and silly mis calculations have seen my child element been taken into 100s less. I should get 747 monthly child element and 317 for me and some months I've had 447 which has led me to food banks and living in poverty. I was financially better off not claiming anything for myself and living off my ctc previously as it was 200 a week so worked out at 800 monthly. Obviously I knew nothing about the complications of it all or I wouldn't of made a claim for jsa in first place. I was wondering if I can do anything to challenge this? I've tried to set up self employed in the meantime AND have been punished and sanctioned for not doing the new enterprise as the mentor kept cancelling and wasee useless and no help. Thanks for reading